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Not a boost straight up to escape velocity, just sufficient added momentum to make a significant economic saving on fuel cost, mass and complexity of a standard launch. It seems ludicrous to me how much fuel in a standard launch appears to be wasted pushing thousands of tonnes of rocket fuel in a vertical direction from a standing start.

The system I envisage would have a horizontal track of possibly 2-3km (distance to be debated), acceleration via external systems (electromag or JATO?), continue up a ramp of slowly increasing gradient, with craft's own engines now running, and exit the ramp at between Mach 1 or 2. Safety run-off track if craft's own engines fail to ignite properly. Winged style craft for stability from ramp & shuttle-style landing.

Similar I know to the Phys.SE 'Rail gun' question here, but acceleration could be more survivable. Had a longer script but it appeared to over-run the site limit. Acknowledge AdamRedwine's railgun question -would have added my contribution to that but my Reputation today is only 1.

Acknowledge Gerry Anderson's Fireball XL5 puppet show on British TV in the '60s - the launch concept has always stayed with me! Submitted for criticism.


marked as duplicate by Brandon Enright, Kyle Kanos, John Rennie, Qmechanic Apr 2 '14 at 20:41

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    $\begingroup$ it's been done, with varying degrees of success, in ancient sci-fi movies and Wile E Coyote inventions :-) . In seriousness, I think you'll find that practical limitations like the length and final altitude of your ramp will lead to failure. And in fact, Mach1 or Mach2 won't get you close to escape velocity, especially in light of atmospheric resistance. $\endgroup$ – Carl Witthoft Mar 31 '14 at 14:43
  • $\begingroup$ In the longer script I wrote, I covered some of this, but when posted, most of it fell off the end (rather like your comedic Wile E Coyote image). I envisaged getting in to the low Mach numbers only as a good start. The resultant fuel saving to the mass of the spacecraft, as its own motors took over the job of acceleration, would be massive compared to lifting vertically from 0 km/h. As to the practicality; that's what I was hoping to get discussed! $\endgroup$ – Judge Zeppelin Mar 31 '14 at 14:52
  • $\begingroup$ possible duplicate of What is the possibility of a railgun assisted orbital launch? $\endgroup$ – Chris Mueller Mar 31 '14 at 15:31
  • $\begingroup$ Yes, I acknowledged that in my script - I would have added my queries to AdamRedwine's railgun question, but it was blocked to members with less than 10 reputation points. currently I've gone from 1 to 8 on Rep score, so I still can't comment on his question. I agree its's similar, but not a duplicate. $\endgroup$ – Judge Zeppelin Mar 31 '14 at 15:33

This concept has gotten consideration from NASA. In the NASA MagLifter concept, a 300-600 miles per hour speed on a superconducting magnetic levitation track appoximately 2.5 miles long and going up a mountain to about 10,000 feet is proposed.

The option of using a helium filled tunnel to reduce drag was also proposed.

  • $\begingroup$ I'll probably tag this a an appropriate answer soon - If NASA has done some sums on this I can ask for nothing more. In the credibility stakes, I'll plump for NASA over a Warner Brothers' cartoon character every day! I notice people stop reading some posts when an 'acknowledged' answer is posted, so I'll give it a little time and see if any other answers come in. The Helium filled tunnel sounds inventive, as the alternative of trying to reduce a 2.5 mile tunnel to a near vacuum would probably be as as expensive as pushing thousands of tons of liquid oxygen and hydrogen etc straight up. Thanks. $\endgroup$ – Judge Zeppelin Mar 31 '14 at 15:10
  • $\begingroup$ here's a link to more-recent NASA info than the one in my answer: nasa.gov/topics/technology/features/horizontallaunch.html Less detail, but suggests this is still under consideration. $\endgroup$ – DavePhD Mar 31 '14 at 15:17
  • $\begingroup$ @JudgeZeppelin also: psfc.mit.edu/~radovinsky/papers/32.pdf Just search "Maglifter" and you'll find tons of info on this $\endgroup$ – DavePhD Mar 31 '14 at 15:21

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